On Thu, May 13, 2021 at 05:38:51PM +0900, AKASHI Takahiro wrote:
On Thu, May 13, 2021 at 05:18:36PM +0900, Masami Hiramatsu wrote:
2021年5月13日(木) 16:24 AKASHI Takahiro takahiro.akashi@linaro.org:
> BTW, IMHO, if u-boot.bin can not find the ESL in the device tree, > it should skip authentication too.
In this case the capsule should be rejected (if CONFIG_EFI_CAPSULE_AUTHENTICATE=y).
That's basically right. But as I mentioned in my comment against Sughosh's patch, the authentication process will be enforced only if the capsule has an attribute, IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED.
That would be a security desaster.
The requirement that I mentioned above is clearly described in UEFI specification. If you think that it is a disaster, please discuss the topic in UEFI Forum first.
I confirmed UEFI specification, version 2.7, Section.23.1 the last of EFI_FIRMWARE_MANAGEMENT_PROTOCOL.GetImageInfo()
If IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED is supported and clear, then authentication is not required to perform the firmware image operations.
Thank you for citing this.
Oh, this is really crazy because deciding whether to authenticate the suspicious package or not, depends on whether the package said "please authenticate me" or not. :D
Well, the attributes can been fetched with GetInfo API, but how it is managed depends on the implementation of FMP drivers.
As I proposed somewhere else, those attributes should be maintained in a separate place (maybe as part of system's policy), presumably ESRT or platform-specific internal database?
FWIW I personally don't think we should even have a config option. But even if we did it certainly must not be dictated by a hardware config.
When you install distro packages you accept whatever dependencies the package has. mkeficapsule is a capsule creation and signing tool. I don't see any reason for keeping the creation and signing apart.
Regards /Ilias
-Takahiro Akashi
Anyway, since this behavior follows the specification, it should be kept by default, but also IMHO, there should be a CONFIG option to enforce capsule authentication always.
Thank you,
-- Masami Hiramatsu